In recent years, as an environmentally-friendly vehicle, attention is being given to a vehicle having mounted thereon a power storage device (e.g., a secondary battery, a capacitor or the like) and running using driving force produced from electric power stored in the power storage device. Examples of such a vehicle include an electric vehicle, a hybrid vehicle, a fuel-cell vehicle, and the like. A technique for charging the power storage device mounted on such a vehicle by a commercial power supply of high power generation efficiency has been proposed.
Among hybrid vehicles, a vehicle in which a vehicle-mounted power storage device can be charged by a power supply outside the vehicle (hereinafter also briefly referred to as an “external power supply”) similarly to an electric vehicle is known (hereinafter also briefly referred to as “external charging”). For example, a so-called “plug-in hybrid vehicle” is known, whose power storage device can be charged by a power supply at an ordinary house by connecting a plug receptacle provided at the house and a charging inlet provided for the vehicle with a charging cable. Accordingly, it can be expected that fuel consumption efficiency of the hybrid vehicle is increased.
Depending on the running state, such a hybrid vehicle may run only with driving force using electric power from the power storage device with the engine combustion operation intermittently stopped during running. In such a case, the temperature of a catalyst for cleaning up an exhaust gas from the engine drops with time. Then, if the temperature of the catalyst has fallen below a catalytic activation temperature at the next engine startup, the exhaust gas cannot be cleaned up appropriately, but discharge of a substance leading to air pollution may be increased.
Japanese Patent Laying-Open No. 2010-018181 (PTD 1) discloses a technique in which, when there is a request to warm up a catalyst due to a drop in temperature of the catalyst in a hybrid vehicle having a catalyst warming-up device (hereinafter also referred to as EHC (Electrical Heated Catalyst)), the EHC is driven using electric power from a power storage device to warm up the catalyst.